Hi,
In our doc and internal sites, there is no existing sample which describes
the use of 3des alg to encrypt string with pure c-style crypto interface.
It should not that complicated as you image, you just need to create a
random bytes (eg 8bytes) and appended to the front of the plaintext. then
you can get the key by calling CryptGenKey or CryptDeriveKey with CALG_3DES
as rc2. Please note that, to use 3des alg, you need to specify
MS_ENHANCED_PROV when calling CryptAcquireContext.